D6ugDyAH

1/*
2   Source for ida_patcher
3   Copyright (c) 2006 Chris Eagle cseagle at gmail.com
4      
5   This program is free software; you can redistribute it and/or modify it
6   under the terms of the GNU General Public License as published by the Free
7   Software Foundation; either version 2 of the License, or (at your option) 
8   any later version.
9   
10   This program is distributed in the hope that it will be useful, but WITHOUT
11   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 
12   FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 
13   more details.
14   
15   You should have received a copy of the GNU General Public License along with 
16   this program; if not, write to the Free Software Foundation, Inc., 59 Temple 
17   Place, Suite 330, Boston, MA 02111-1307 USA
18*/
19
20/*
21 * This program reads an Ida Pro generated .dif file and applies
22 * the differences to the original binary to create a patched binary
23 * The program will infer the name of the binary from the content of 
24 * the dif file, or take the name as a command line option.
25 * CAUTION: The program transforms the input binary so if you wish
26 * to preserve the original binary make sure you make a copy and
27 * transform the copy.
28 */
29
30#include <stdio.h>
31
32int main(int argc, char **argv) {
33   char line[256];
34   FILE *patch = stdin;
35   FILE *input = NULL;
36   unsigned int offset;
37   int orig;
38   int newval;
39  
40   int i;
41  
42   for (i = 1; i < argc; i += 2) {
43      if (!strcmp(argv[i], "-p")) {
44         if ((i + 1) < argc) {
45            FILE *f = fopen(argv[i+1], "r");
46            if (f) {
47               patch = f;
48            }
49            else {
50               fprintf(stderr, "Failed to open patch file %s\n", argv[i+1]);
51               exit(0);
52            }
53         }
54      }
55      else if (!strcmp(argv[i], "-i")) {
56         if ((i + 1) < argc) {
57           fprintf(stderr, "Opening %s\n", argv[i+1]);
58            input = fopen(argv[i+1], "rb+");
59            if (input == NULL) {
60               fprintf(stderr, "Failed to open input file %s\n", argv[i+1]);
61               exit(0);
62            }
63         }
64      }
65      else {
66         fprintf(stderr, "usage:\n\t%s [-i <binary>] [-p <dif file>]\n", argv[0]);
67         fprintf(stderr, "\t%s [-p <dif file>]\n", argv[0]);
68         fprintf(stderr, "\t%s [-i <binary>] < <dif file>\n", argv[0]);
69         fprintf(stderr, "\t%s < <dif file>\n", argv[0]);
70         exit(0);
71      }
72   }
73
74   if (patch == stdin) {
75      fprintf(stderr, "Reading patch data from stdin.\n");
76   }
77   fgets(line, sizeof(line), patch); /* eat dif file intro line */
78   fgets(line, sizeof(line), patch); /* eat blank line */
79   
80   if (input == NULL) {
81      fprintf(stderr, "Inferring input file name from patch file data.\n");
82	   fscanf(patch, "%256s", line);
83      input = fopen(line, "rb+");
84      if (input == NULL) {
85         fprintf(stderr, "Failed to open input file %s\n", line);
86         exit(0);
87      }
88   }
89   else { /* don't need input file name, but need to skip it in dif file */
90	   fgets(line, sizeof(line), patch);
91	}
92
93   while (fscanf(patch, "%x: %x %x", &offset, &orig, &newval) == 3) {
94      fseek(input, offset, SEEK_SET);
95      if (fgetc(input) == orig) {
96	      fseek(input, offset, SEEK_SET);
97	      fputc(newval, input);
98      }
99      else {
100         //original bytes don't match expected?
101      }
102   }
103   fclose(input);
104   if (patch != stdin) {
105      fclose(patch);
106   }
107}